The present invention relates to a lifting or elevating device with a synchronization mechanism, which is used in a transfer system, in particular with a pneumatic drive, in order to raise and/or lower transported goods.
Many different types of lifting or elevating devices for transfer systems are known. Typically, elevating devices in assembly and automated technologies serve to remove goods, such as work piece carriers, on transfer systems from a longitudinal segment into a transverse segment, or in the reverse, from a transfer segment of the transfer system into a longitudinal segment. In addition, elevating devices serve the purpose of lifting work piece holders from a transfer path, for example, in order to perform an operation at a machining or work station. Such types of elevating devices are known, for example, from the Catalog der Anmelderin Transfersystem TS 4, Ausgabe 3.0, 1997. Here, the elevating device has a number of pneumatic cylinders for performing the lifting movement. The pneumatic cylinders represent additional manufactures, which have very high manufacturing costs. In addition, the elevating devices themselves are constructed to be relatively high, since the cylinder rods also project at a distance from the cylinders. Therefore, when laying out the transfer system, it is usually not possible to operate several transfer segments over one another, since the elevating unit would be too high.
A further disadvantage of known elevating devices is that the individual cylinders of the elevating device are indeed commonly controllable, however, usually an asynchronous movement of the individual lifting cylinder occurs, which leads to a non-uniform lifting of the goods through the elevating device. The common control, therefore, cannot guarantee synchronous movement of the lifting cylinders. In extreme cases, this can lead to a tilting of the elevating device and to damage to the transported goods.